Add post-install verification phase

Verify the SHA sum of all patched and extracted files after
a file system remount.

Bug: 18145574

Change-Id: I2f053d085543e10e39153a774542d37ee0a238bd

tools/releasetools/edify_generator.py

@@ -323,6 +323,10 @@ class EdifyGenerator(object):
     """Append text verbatim to the output script."""
     self.script.append(extra)
 
+  def Unmount(self, mount_point):
+    self.script.append('unmount("%s");' % (mount_point,))
+    self.mounts.remove(mount_point);
+
   def UnmountAll(self):
     for p in sorted(self.mounts):
       self.script.append('unmount("%s");' % (p,))